正解:B
Radio-frequency identification (RFID) is the most appropriate protocol to use for inventory tracking in a small warehouse. RFID is a technology that uses radio waves to identify and track objects that have RFID tags attached to them. RFID tags are small devices that store information about the object, such as its name, serial number, location, or status. RFID tags can be passive, which means they do not have a battery and rely on the radio signal from the reader to power them, or active, which means they have a battery and can transmit their own signal. RFID readers are devices that can scan the RFID tags and read the information stored on them.